The present invention relates, in general, to a safety belt, and in particular to a safety belt for use in an aircraft or military vehicles with limited space of movement.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Safety belts for use in seats of aircrafts for example, can be designed in the form of a lap belt which, when unbuckled, automatically are pulled in. The lap belt has a belt webbing which has one end secured to a rotating length adjuster of a belt takeup and another end which has a tongue for insertion in a buckle and locking by a buckle latch in the buckle. When buckled up, the occupant is protected against potential harm in the event of turbulences. The length adjuster has a winding reel which is constantly biased in the direction of retraction of the belt webbing, and a locking mechanism to lock the length adjuster when the belt webbing has been pulled out and the length adjuster has pulled back about 25 mm of the belt webbing into the belt takeup. The belt takeup is locked but still pulls in any slack beyond 25 mm. This causes discomfort for the occupant and gives the occupant the feeling of being “chocked”.
In automatic belts, a spring-biased length adjuster is provided on one end of the belt webbings and, when installed in an automobile, reacts and locks in the event of a sudden slow down of the vehicle (vehicle-sensitive), or when used in aviation, reacts to a belt acceleration (belt-sensitive) to lock the length adjuster and thus to prevent further belt pay out. Length adjusters of this type lock only in pay-out direction but not in winding direction. In the event, an occupant sits on a springy or compressible seat of a vehicle, any bumps in the road surface will thus compress the seat, causing the vehicle-sensitive length adjuster to pull in the belt webbing, while remaining locked as a result of vehicle shaking or vehicle accelerations, so that the belt webbing shortens across the occupant's body. This scenario repeats itself, causing the belt webbing to progressively tighten until becoming so taut that the occupant has to unbuckle.
It would therefore be desirable and advantageous to provide an improved safety belt to obviate prior art shortcomings and to enhance the comfort for the occupant.